Upon visiting a place frequented by the public, somebody who is responsible for a dependent person, a guardian, typical case being a parent of a child, is in a constant state of apprehension, and occasionally in great fear, that the dependent will become separated and lost. This can happen either because the guardian and the dependent inadvertently wander away from each other, or worse, there is the possibility of foul play, such as an attempted abduction of the dependent.
Today we have Radio Frequency Identification (RFID) technology. RFID technology is well know in the art. The roots of this technology go back over two decades, and by now it is becoming pervasive. Basically it has three components: a RFID tag, a RFID reader device, and a host processor. The RFID tag and RFID reader device, which is also commonly called interrogator device, are both equipped with antennas and can communicate with each other at radio frequencies. The RFID tag can be passive or active type. A passive RFID tag has no source of power of its own, while an active one is independently powered. RFID tags can also be sorted as read only ones or read/write ones. The processor directs communications between the RFID tag and RFID reader device and contains most of the software to run the particular RFID technology application. At any given location the processor can keep track of a very large number of individual reader devices and tags. For simplicity and brevity, from here on the RFID tag at times may be referred to only as “tag”, and the RFID reader device only as “reader device”, or “reader”. Components of the technology are commercially readily available, from a variety of companies, such as Motorola Inc., Texas Instruments Inc., Intermec Technologies Corp., and others. Processors suitable for the task additionally can also be found at many computer vendors, such as International Business Machines Corp., Sun Microsystems Inc., Dell Inc., Hewlett Packard Co., and others.
A further look at the background of RFID technology can be gleaned from this sample list of U.S. Pat. Nos. 5,528,222; 5,550,547; 5,673,037; 5,673,037; 5,912,632; 5,995,019; 6,204,765; 6,215,402; 6,429,775 with all of these patents herein incorporated by reference. Also large amount of information regarding RFID technology is available on the Internet, some of if from the providers of the technology, apparently for the education of their customers.
Using RFID technology to track people, animals, objects, etc., has been disclosed earlier, for instance, in US patents “Method and apparatus for tracking and locating personnel” U.S. Pat. No. 5,977,913, and “Object control and tracking system with zonal transition detection” U.S. Pat. No. 6,427,913, but these patents do not teach the present invention. U.S. Pat. No. 6,753,782 “System for monitoring patients with Alzheimer's disease or related dementia” uses RFID technology to track, monitor, and protect Alzheimer patients, but does not teach the present invention.